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Background The conventional scores of the neuropsychological batteries are not fully optimized for diagnosing dementia despite their variety and abundance of information. To achieve low-cost high-accuracy diagnose performance for dementia using a neuropsychological battery, a novel framework is proposed using the response profiles of 2666 cognitively normal elderly individuals and 435 dementia patients who have participated in the Korean Longitudinal Study on Cognitive Aging and Dementia (KLOSCAD). Methods The key idea of the proposed framework is to propose a cost-effective and precise two-stage classification procedure that employed Mini Mental Status Examination (MMSE) as a screening test and the KLOSCAD Neuropsychological Assessment Battery as a diagnostic test using deep learning. In addition, an evaluation procedure of redundant variables is introduced to prevent performance degradation. A missing data imputation method is also presented to increase the robustness by recovering information loss. The proposed deep neural networks (DNNs) architecture for the classification is validated through rigorous evaluation in comparison with various classifiers. Results The k-nearest-neighbor imputation has been induced according to the proposed framework, and the proposed DNNs for two stage classification show the best accuracy compared to the other classifiers. Also, 49 redundant variables were removed, which improved diagnostic performance and suggested the potential of simplifying the assessment. Using this two-stage framework, we could get 8.06% higher diagnostic accuracy of dementia than MMSE alone and 64.13% less cost than KLOSCAD-N alone. Conclusion The proposed framework could be applied to general dementia early detection programs to improve robustness, preciseness, and cost-effectiveness.

Background: Although the Mini-Mental Status Examination (MMSE) is the most widely used screening instrument for dementia, it has several limitations. Methods: We developed and validated a new scoring method of the MMSE, namely the short form of the MMSE (MMSE-S). Results: The MMSE-S was more robust to demographic influences than the MMSE. The influence of education, in particular, was smaller in the MMSE-S compared to the MMSE (p < 0.01). The diagnostic accuracy of the MMSE-S for very mild to mild dementia was also better than that of the original MMSE (p < 0.0001). Its specificity, in particular, was higher than that of the original MMSE. In Korea, we could improve the post-test probability for dementia from 46.88 to 64.76% by employing the MMSE-S instead of the MMSE. We also provided optimal cut-off scores for dementia stratified by age, education, and gender, which may further improve the diagnostic accuracy of the MMSE-S for dementia. Conclusion: Due to its good accuracy and brevity, the MMSE-S may contribute to enhancing the cost-effectiveness of and accessibility to dementia screening as well as early diagnosis and treatment of dementia, particularly in low- and middle-income countries.

To investigate cognitive function in patients with early and late age-related macular degeneration (AMD) compared with an elderly, community-dwelling Korean population without AMD.Case-control study.We enrolled 170 AMD patients and 190 non-AMD community-based controls.A comprehensive battery for cognitive function evaluation consisting of 15 psychological tests, including a depression evaluation test, was used. Cognitive function scores were adjusted for age, gender, education, and visual acuity (VA). We categorized AMD as early AMD, exudative AMD, or geographic atrophy.The primary outcome measure was the degree of cognitive impairment, as assessed by the Korean versions of the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychological Assessment Battery, Benton Visual Retention Test, and Digit Span Test Forward and Backward.Patients with AMD showed lower global cognition scores than did normal controls (mean Mini-Mental State Examination [MMSE] score, 24.97 vs 25.99; P0.001). Among cognitive functions, visuospatial function, verbal memory, visual memory, and frontal function were impaired in AMD patients relative to normal controls. The rate of mild cognitive impairment (MCI) was higher in AMD patients than in controls (52.4% vs 26.8%; P0.001), with an odds ratio (OR) of 3.127 (95% confidence interval, 1.855-5.271) after adjustment for age, education, and VA. Geographic atrophy was associated with the highest risk of MCI (OR, 4.431; 95% confidence interval, 1.413-13.898) and a clinically significant reduction in MMSE scores (23.42) relative to the controls. There was a trend of worsening cognitive function test scores from the controls to the early AMD, then the exudative AMD, and finally the geographic atrophy patients, after adjustment for covariates. AMD patients with poor VA (≤20/100) had 6 times the risk of MCI as AMD patients with good or moderate VA (20/100).Patients with AMD, especially those with the geographic atrophy subtype, are at greater risk for cognitive impairment than are non-AMD control subjects. In the visual rehabilitation of AMD patients, potential cognitive impairment should be taken into consideration.

Background: We developed the Korean version of the Frontal Assessment Battery (FAB-K), evaluated its psychometric properties and constructed normative data for Korean elders. Methods: FAB-K was administered to 300 Alzheimer’s disease (AD) patients and 635 normal controls. Reliability of FAB-K was evaluated by testing its internal consistency, test-retest and inter-rater reliabilities. Validity of FAB-K was evaluated by testing discriminant validity for AD and concurrent validity with other frontal function tests. Age- and education-specific normative data of FAB-K were developed. Results: Cronbach’s α, inter-rater reliability and test-retest reliability of FAB-K were 0.802, 0.980 (p < 0.001) and 0.820 (p < 0.001), respectively. FAB-K exhibited significant correlations with the scores of MMSE and other frontal function tests (p < 0.01). Total and item scores of FAB-K were lower in AD patients than in controls and became worse as clinical dementia rating increased (F = 192.026, d.f. = 4, p < 0.001). The optimal cut-off score of FAB-K for AD was determined as 10/11, where sensitivity and specificity for AD were 0.717 and 0.827, respectively. Normative data were stratified by 3 age groups and 4 education groups. Conclusion: The FAB-K is a valid and reliable instrument for evaluating frontal dysfunction, and may be useful for screening AD.

Aim: We aimed toevaluatethe psychometric properties of the Subjective Memory Complaints Questionnaire (SMCQ). Methods: The reliability of the SMCQ was evaluated by testing its internal consistency and test-retest reliability. Pearson correlation analyses were performed to assess the concurrent validity. Confirmatory factor analysis was used to evaluate the construct validity. Diagnostic ability for dementia was tested with receiver operator characteristic curve analyses. Results: Cronbach’s α coefficient and intraclass correlation coefficients of the SMCQ were 0.864 and 0.828 (p < 0.001), respectively. The SMCQ scores were significantly correlated with the scores on Camdex Memory Complaint Questionnaire, Seoul Informant Report Questionnaire for Dementia and cognitive tests from the CERAD (Consortium to Establish a Registry for Alzheimer’s Disease) neuropsychological test battery (p < 0.01). The results of confirmatory factor analyses confirmed that the SMCQ consisted of subjective memory complaints (SMC) for general memory and for everyday memory. The SMCQ score discriminated well between nondemented elderly without dementia and those with dementia (p < 0.01). The area under the curve value of the SMCQ was 0.84, indicating that it had high diagnostic ability. Conclusion: The SMCQ was found to be a brief, reliable and valid questionnaire for evaluating SMC. It might be useful for evaluating the cognition of elderly subjects when reliable informants are not available.

Background/Aims: This study aimed to develop a brief, reliable and valid test for cognitive function of severely demented patients. Methods: We constructed the Severe Cognitive Impairment Rating Scale, which consisted of 11 items covering memory, language, visuospatial function, frontal function and orientation, and investigated its reliability and validity on 267 subjects [normal: 65, very mild Alzheimer’s disease (AD): 42, mild AD: 58, moderate AD: 36, severe AD: 44, profound AD: 22]. Results: The internal consistency obtained by Cronbach’s coefficient α was 0.93. The interrater reliability and test-retest reliability in the moderately to severely impaired subjects with an MMSE score of ≤14 was 0.99 (p < 0.001) and 0.90 (p < 0.001), respectively. It showed significant correlation with Severe MMSE (r = 0.96, p < 0.01), MMSE (r = 0.86, p < 0.01) and Clinical Dementia Rating (r = –0.83, p < 0.01). It was robust to both the floor effect in the severe/profound stage of AD and the ceiling effect in the mild/moderate stage of AD. Exploratory factor analysis yielded 2 factors (automatic informational processing and controlled informational processing) accounting for 73.5% of the total variance. Conclusions: The Severe Cognitive Impairment Rating Scaleis a valid and reliable test for evaluating the cognitive function of advanced AD patients.

Background/Aims: To compare the prevalence and characteristics of depression in vascular dementia (VaD) and Alzheimer’s disease (AD) after adjusting for dementia severity and gender. Methods: One hundred and eight pairs of VaD and AD patients matched for dementia severity and gender were assessed. Results: Major depressive disorder (MDD) was more prevalent in the VaD group than in the AD group (20.4% in VaD, 10.2% in AD, p = 0.04, Cochran-Mantel-Haenszel, CMH, test) regardless of the dementia severity and gender. The odds ratio for developing MDD in the VaD group versus the AD group was estimated to be 2.20 (95% confidence interval = 1.02–4.74). Neurovegetative symptoms such as ‘felt tired and weak all the time’ (30.6% in VaD, 13.9% in AD, p = 0.003, CMH test) and ‘changed weight without trying’ (16.7% in VaD, 6.5% in AD, p = 0.02, CMH test) were more prevalent in the VaD group than in the AD group. Conclusion: Depression in VaD was quantitatively and qualitatively different from that in AD regardless of the severity of dementia and gender; depression was more prevalent, severer and more retarded and vegetative in VaD than in AD.

To investigate the nature of frontal dysfunction associated with chronic kidney disease (CKD) in people without stroke or depressive disorders.Cross-sectional.Community based.Five hundred twenty-nine community-dwelling participants.Participants with CKD were classified into one of three diagnostic groups based on their estimated glomerular filtration rate (eGFR): normal (≥ 60.0 mL/min per 1.73 m(2)), mild CKD (45.0-59.9 mL/min per 1.73 m(2)), or moderate to severe CKD (45.0 mL/min per 1.73 m(2)). Cognitive function was assessed using the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychological Assessment Battery, lexical fluency, digit span test, and the 64-card Wisconsin Card Sorting Test.Perseverative responses and perseverative errors were significantly more prevalent in the group with moderate to severe CKD than in those without CKD and those with mild CKD. The mean number of perseverative responses was 28.6 ± 16.9 in participants with moderate to severe CKD, 19.0 ± 11.4 in those with mild CKD, and 17.1 ± 10.6 in those without CKD (P.001, ANCOVA). The mean number of perseverative errors was 23.1 ± 12.3 in participants with moderate to severe CKD, 16.2 ± 8.3 in those with mild CKD, and 14.8 ± 7.8 in those without CKD (P.001, analysis of covariance). The odds ratios in the fully adjusted model for the presence of moderate to severe CKD for perseverative responses and perseverative errors were 4.82 (95% confidence interval (CI) = 2.14-10.85, P.001) and 5.01 (95% CI = 2.22-11.28, P.001), respectively.Frontal dysfunction, particularly perseverative errors and responses, was associated with moderate to severe CKD in the population studied.